Portable power supply



FIG. 1 is a front, left and top side perspective view of a portable power supply showing the new design;

FIG. 2 is a rear, right and bottom side perspective view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a left side view thereof;

FIG. 6 is a right side view thereof;

FIG. 7 is a top view thereof; and,

FIG. 8 is a bottom view thereof.

The broken lines are for the purpose of illustrating portions of the portable power supply that form no part of the claimed design. 

CLAIM The ornamental design for a portable power supply, as shown and described. 